Sickle cell disease: An international survey of results of HLA-identical sibling hematopoietic stem cell transplantation

Despite advances in supportive therapy to prevent complications of sickle cell disease (SCD), access to care is not universal. Hematopoietic cell transplantation is, to date, the only curative therapy for SCD, but its application is limited by availability of a suitable HLA-matched donor and lack of awareness of the benefits of transplant. Included in this study are 1000 recipients of HLA-identical sibling transplants performed between 1986 and 2013 and reported to the European Blood and Marrow Transplant, Eurocord and the Center for International Blood and Marrow Transplant Research. The primary endpoint was event-free survival, defined as being alive without graft failure; risk factors were studied using Cox regression model. The median age at transplantation was 9 years and the median follow-up, longer than 5 years. Most patients received a myeloablative conditioning regimen (n=873; 87%) and the remainder, reduced-intensity conditioning regimens (n=125; 13%). Bone marrow was the predominant stem cell source (n=839; 84%), while peripheral blood and cord blood progenitors were used in 73 (7%) and 88 patients (9%), respectively. The 5-year event-free and overall survival was 91.4% (95% CI 89.6%-93.3%) and 92.9% (95% CI 91.1%-94.6%), respectively. Event-free survival was lower with increasing age at transplantation (hazard ratio [HR] 1.09; p